The field of this invention relates to a sound attenuation apparatus to diminish the level of sound emitted from a specific source, and more particularly to a sound attenuation apparatus for an airstream duct to diminish the sound that is produced by the device that is producing the air movement through the duct.
The moving of a gas through a duct system is exceedingly common within industry. A typical gas would be air. A common form of a device to move air through the duct system would be a blower. The basic construction of the blower would comprise a shaft upon which are mounted fan blades. Rotation of the blades results in air movement downstream of the blades. This air movement is directed by the duct system to a particular location.
Because of the physical size of the blower, it is common that a substantial amount of noise will be generated in its operation. To any individual working in close proximity to the blower, the noise generated not only can be annoying, but actually can be damaging to one's ears after a period of time.
It has been found that, like the air itself, the noise is directed downstream of the duct. It has been known in the past to connect some type of sound absorption apparatus in conjunction with the airstream to attenuate the sound produced by the blower while yet permitting the flow of the air through the duct to occur in a substantially unrestricted manner. There is a need to improve upon the efficiency of this attenuation so that the greater percentage of the sound is absorbed at a minimum manufacturing cost for the attenuation apparatus.